Braking systems for automobiles, trucks, buses, and motor homes typically include a push rod actuated master cylinder for generating a hydraulic pressure that is transmitted through brake lines to actuate hydraulic brakes attached to the wheels of the vehicle. The actuation of the brakes acts to slow or stop the vehicle. It is desirable in such hydraulic brake systems for vehicles to include a power brake booster for augmenting the force applied to a brake pedal connected to the push rod. The power brake booster allows the operator to operate the brakes with a reduced amount of force to the brake pedal.
Known power brake boosters typically utilize engine vacuum, hydraulic pressure, or pneumatic pressure to drive one or more pistons connected to the master cylinder for augmenting the force applied to the master cylinder via the push rod when the operator is pushing on the brake pedal. One source for vacuum for use in the power brake booster is the vacuum created in the induction system of a running internal combustion engine. Vacuum may also be provided by an engine driven or electrically driven vacuum pump. Hydraulic pressure or pneumatic pressure actuated power brake boosters require a source of pressure such as the power steering pump or a hydraulic boost pump for hydraulic systems or an air compressor for pneumatic systems. These known systems suffer from the drawback that they require a plurality of components that may fail or not function properly during times when the engine is not running.
Another drawback of known systems is that the power brake booster system takes up a large amount of space and is generally placed in the engine compartment. The positioning of the power brake booster in the engine compartment reduces the amount of space in the engine compartment for larger engines or other engine components. The space in the engine compartment is particularly important in the assembly of custom vehicles or vehicles requiring a large number of accessory components.
What is needed is a power brake booster system that provides augmentation to the braking system, occupying a small amount of space, being operable during times when the engine is not running and not suffering from the drawbacks of known braking systems.